The present invention relates to a protecting cap for a Banjo member used in a Banjo type joint. The protecting cap is suitable particularly for preventing damage of a pair of parallel sealing surfaces formed on a connecting sleeve of a Banjo type joint.
As shown in FIG. 15A, a Banjo type joint comprises a Banjo member 1 connected and fixed to one end of a metallic pipe 4, the Banjo member 1 having a cross hole 2c and a pair of parallel sealing surfaces 2d and 2e. In order for the Banjo member 1 to be easily connected and fixed to one end of the pipe 4, the Banjo member 1 is provided with a cylindrical base portion la orthogonal to the cross hole 2c which is formed in a connecting sleeve 2. Various connecting sleeves 2 slightly different in axial thickness are adopted.
Another example of a Banjo type joint is shown in FIG. 15B, in which a cross hole 2c formed in a pair of parallel sealing surfaces 2d and 2e of a connecting sleeve 2 has openings 2a1 and 2a2 of different diameters. Various such Banjo type joints are also adopted.
There also is adopted such a Banjo type joint as shown in FIG. 15C, in which a Banjo member 1 does not have a base portion and substantially a connecting sleeve 2 is connected and fixed to one end of a pipe 4.
The Banjo type joint is used for connecting a piping part such as a flexible hose firmly to a mating member. For example, it is used for connecting a fuel pump to a delivery pipe without leakage of fuel in an automobile. Generally, in an automobile manufacturer, the Banjo member 1 as an assembled product with a flexible hose such as rubber hose fitted beforehand in the opposite end (not shown) of the pipe 4 of the Banjo type joint is connected to a pipe such as a delivery pipe with a Banjo bolt having a head portion.
Such an assembled product is fabricated and connected to a pipe 4 in the following manner. In a hose manufacturer, a large number of Banjo members 1 and pipes 4 are manufactured each individually beforehand, then one ends of the pipes 4 are connected and fixed to the base portions la of the Banjo members 1 to once produce a large number of Banjo type joints. Thereafter, flexible hoses are firmly fixed respectively to the opposite ends of the pipes 4 with use of metallic joint pieces such as a sleeve. A plurality of the thus-assembled products are then gathered and packed into a case and thereafter the thus-encased plural assembled products are conveyed from the hose manufacturer to an automobile manufacturer, which in turn connects the assembled products to pipes such as delivery pipes in automobiles with use of Banjo bolts.
In the automobile manufacturer, one parallel sealing surface 2d and the other parallel sealing surface 2e parallel to each other of the connecting sleeve 2 in the Banjo member 1 of such a Banjo type joint are held in a liquid-tight manner between a smooth surface of the mating member and a head portion of the Banjo bolt. Therefore, the parallel sealing surfaces 2d and 2e are machined in an extremely smooth state.
For this reason, it has been desired to provide a protecting cap for protecting the parallel sealing surfaces 2d and 2e to prevent the parallel sealing surfaces 2d and 2e from being flawed not only during manufacture of the Banjo type joint after fabrication of the Banjo member 1 but also during handling and conveyance until connection of the assembled product to the mating member on the customer side.
Heretofore, as to the protecting cap of this type, a rubber hose has been used as a flexible hose to be connected and fixed to the opposite end of the pipe, and in compliance with a customer's request it is necessary to use an adhesive for connecting and fixing the hose and the pipe to each other which adhesive requires a heat treatment. Therefore, the protecting cap used has been required to possess heat resistance.
As conventional protecting caps are known rubbery protecting caps capable of having cylindrical portions of being fitted in cross hole openings of different diameters, the cylindrical portions having flanges capable of coming into surface contact with sealing surfaces of a connecting sleeve and also having outside diameters capable of being fitted in the cross hole openings of different diameters. However, in order to prevent such rubbery protecting caps from coming off the connecting sleeve, it has been necessary particularly for the cylindrical portions to match the cross hole openings of different diameters. Besides, in both material cost and machining cost, rubbery protecting caps have been more expensive than resinous protecting caps.
Further, since there are a variety of Banjo type joints slightly different in axial thickness and cross hole opening diameter, it is required to provide a variety of protecting caps accordingly. Consequently, the storage and management of protecting caps become troublesome and so does the replacement of protecting caps.
By the way, a resin hose has come to be adopted as the flexible hose connected and fixed to the opposite end of the pipe. In the case of a resin hose, it is not necessary to conduct a heat treatment for connecting and fixing the resin hose to the opposite end of the pipe. The object of hose requiring a heat treatment now shows a downward trend with spread of such a resin hose.
According to the conventional way of doing, the expensive rubbery protecting caps are used repeatedly before shipping, and at the time of shipping the rubbery protecting caps are replaced with less expensive, resinous protecting caps which are not resistant to heat and which are of the same shape as the rubbery protecting caps.
Further, a tube connector provided with a protecting cap is known from U.S. Pat. No.5,403,041.
The tube connector disclosed in the U.S. patent is provided with a connecting sleeve of the Banjo type joint, which has a cross hole for receiving together therein two sealing gaskets and a Banjo bolt for fixing to a mating member and also has a pair of parallel sealing surfaces.
The gaskets are brought into surface contact respectively with the paired parallel sealing surfaces, then the Banjo bolt is passed through the cross hole and the gaskets of the connecting sleeve in the Banjo type joint, and the protecting cap is mounted, whereby a Banjo member is held grippingly between a flank at one end of a U-shaped clamp of the protecting cap and a protecting cover at the opposite end, through an extension located at an intermediate position, thereby holding the Banjo bolt and the gaskets so as not to become disengaged from the connecting sleeve.
According to the invention disclosed in the above U.S. patent, the assembling time in an automobile manufacturer can be shortened because the components are respectively manufactured in a division of labor. Besides, there is no fear of falling of such spare mounting units as gaskets and Banjo bolt until the connection of an assembled product to a mating member is completed and hence it is possible to prevent damage to the threads of the Banjo bolt and damage of the paired parallel sealing surfaces. Thus, there accrue various advantages.
In such a tube connector, however, by means of the protecting cap, the Banjo bolt is inserted and held into the cross hole of the connecting sleeve in the Banjo type joint, and the gaskets are mounted beforehand with the Banjo bolt adapted.
Therefore, such the protecting cap is required to have dimensions matching the thickness between the paired parallel sealing surfaces of the Banjo member used, and the length of the Banyo bolt used.
If such a protecting cap is adopted, the gaskets and Banjo bolts held by the protecting cap are bulky and obstructive when the Banjo type joint is manufactured and when a flexible hose is connected and fixed to the opposite end of the pipe in the Banjo type joint. This obstruction is conspicuous particularly during manufacture of the Banjo type joint by an automatic machine such as a robot and when connecting and fixing a flexible hose to the opposite end of the pipe.
The Banjo bolt is not needed at all if it is attached beforehand to the mating member.
In all of the conventional protecting caps, in order to prevent disengagement from the connecting sleeve, it has been necessary to take matching to the diameter of each cross hole opening in each Banjo member and to the thickness between a pair of parallel sealing surfaces of each Banjo member and the length of the Banjo bolt used.
On the other hand, there are a variety of Banjo type joints slightly different in axial thickness and in the diameter of each cross hole opening. For this reason, with respect to each of the foregoing conventional protecting caps, it is necessary to provide various protecting caps for each of Banjo members. Consequently, the storage and management of protecting caps are troublesome and so does the replacement of protecting caps.